Question: Ken can walk $40$ dogs in $8$ hours. How many dogs can Ken walk in $12$ hours?
Solution: We're trying to find the number of dogs Ken can walk in $12$ hours. If in ${8}$ hours, Ken can walk ${40}$ dogs, then in $1$ hour, he can walk $5$ dogs.  So, in ${12}$ hours, Ken can walk ${60}$ dogs.